A series of CoMoO4 hydrates composed of nanorods have been synthesized with different alcohol-water solvent systems, and the corresponding Co-Mo sulfides are obtained after sequential calcination and sulfurization. The characterization results show the change in solvent system can efficiently adjust the particle size of the Co-Mo precursors, while cannot affect their components and morphologies. Because of the different particle size, the specific surface areas (SSA) of the final Co-Mo sulfides are different. The particles with small size can lead to a high SSA that benefits the exposure and dispersion of active components, and further promote the incorporation of MoS2 slabs with Co atoms to form "Co-Mo-S" structures on the surface of the sulfides. More "Co-Mo-S" structures would create more coordinative unsaturated sites with high activity in situ during hydrodesulfurization (HDS) reaction, resulting in a higher HDS activity. Among the Co-Mo sulfides, since S-mew derived from methanol-water system possesses the smallest particle size and the most active sites, it naturally exhibits the highest HDS activity toward dibenzothiophene. (C) 2015 Elsevier B.V. All rights reserved.